1. Area of the Art
The present invention concerns safety devices intended to prevent dangerous falls and more particularly safety harnesses to be worn when working in high places to protect the wearer from an accidental fall.
2. Description of the Prior Art
Safety harnesses are commonly used as part of a fall protection system for persons who must work at heights. In the workplace full-body safety harnesses are often required. Such harnesses, which typically include shoulder straps, can be designed in many alternative manners. For example, U.S. Pat. No. 5,531,292, to Bell discloses a harness with a pair of leg straps, a pair of upper torso straps, a pair of rappelling straps, a seat strap, and four belt suspenders wherein the torso straps include chest strap and back strap portions.
Currently available full-body safety harnesses are generally manufactured from flexible, but relatively inelastic, woven materials such as nylon and polyester. These materials are generally capable of an elastic extension of approximately 1% or less under a tensile load of approximately 10 pounds. Indeed, even at a tensile load of approximately 100 pounds, such materials generally exhibit an elastic extension of approximately 2.5% or less. Although the strength of such materials is suitable for fall protection, the materials are relatively stiff so that harnesses fabricated from such materials impair movement of a worker while in the harness. This impairment often results in discomfort, reduced effectiveness and quick fatigue of the worker. The limited range of motion, discomfort and fatigue associated with current safety harnesses can even result in safety lapses by the worker.
One inventor has provided a partial solution to this problem by disclosing a safety harness constructed from an elastic material (see U.S. Pat. No. 6,006,700 to Cox). It is disclosed therein that providing a harness with limited elastic stretch considerably improves comfort. However, there are still drawbacks. First, the elastic straps necessarily fit snuggly and may chafe. Second, ordinary highly safe strapping material cannot be used because such materials have limited elasticity. This necessitates the use of specially-made elastic strapping material that is more expensive and not necessarily approved by all safety agencies. It would be advantageous if the comfort of elastic strap harnesses could be provided using ordinary safety strap material that is widely available and accepted by all safety agencies.